Portion of Hwy 1 closed due to landslide risk as heavy rain inundates B.C.'s South Coast

The first major storm of the season on B.C.'s South Coast has resulted in the closure of a portion a major highway over concerns of the potential for landslides due to recent wildfires.

Highway 1 between Lytton and Spences Bridge is closed effective Friday at 4 p.m., according to the Ministry of Transportation and Infrastructure.

The ministry says the heavy rainfall poses landslide risks to the area, much of which was destroyed by a wildfire in late June.

"Debris flows are a post-fire hazard that can be triggered by intense rainfall," it said in a statement.

"Drivers should expect to encounter debris along any burnt areas and are advised to plan alternative routes."

A time for reopening that section of Highway 1 has not been announced. The ministry says further closures may be announced with limited notice.

Traffic will be redirected to Highway 5 or Highway 3 and southbound traffic will be diverted at Cache Creek.

The ministry is asking motorists who are travelling through wildfire affected areas to avoid stopping during rainfall events.

Earlier Friday, BC Hydro released a report which found that record-breaking heat between June and August in many parts of the province killed trees or weakened their root systems, which could also lead to outages during the storm.

Rainfall pounds the South Coast

A rainfall warning has been issued by Environment Canada for much of the Lower Mainland, including Metro Vancouver, the Fraser Valley, Fraser Canyon, Howe Sound, the Sunshine Coast and Whistler. There are also special weather statements in effect for Vancouver Island.

The storm arrived on the North Coast along the Alaskan panhandle on Thursday, according to Environment Canada emergency preparedness meteorologist Armel Castellan. 

Significant rainfall is predicted on Friday and Saturday through Sunday morning in Metro Vancouver and Victoria. Clouds are forecast to move in on Thursday night as a Pacific system settles in over the coast and heavy rain is forecast to begin before morning. 

Strong winds gusting up to 80 kilometres per hour may accompany the rain on Friday afternoon. 

About 50 millimetres of rainfall is expected by Friday evening, though Environment Canada predicts Metro Vancouver could see up to 80 millimetres, with even more rain expected in Howe Sound and the North Shore mountains.

Castellan said some areas could see 10 millimetres of rain in one hour.

"Because we haven't really seen too many strong winds and big rain events because it's been such a strong drought signal since early spring, this is going to have potentially high implications for forest health," Castellan said. 

"Potential breaking limbs and trunks, and therefore power outages. Safety is also a concern."

Creeks and rivers could also surge quickly. 

Snow possible at higher elevations

Snow could fall on some highway passes, and Castellan is advising travellers to check road conditions on DriveBC before they head out over the next few days.

CBC meterologist Johanna Wagstaffe says Vancouver received about 74 millimetres of precipitation between June 1 and Sept. 1, which means some areas could receive an entire summer's worth of rain in just one weekend. 

Officials are advising residents to clear leaves and debris from drainage areas, including storm drains on residential streets, as heavy rain could cause flooding.

Temperatures will be in the low to mid-teens through the weekend and into next week. 

Castellan said the storm won't quite reach the Interior, but it may see some rain over the weekend. 

"We're obviously going to see more [storms] as the season goes on," Castellan said. 

"It's like the heat in June, the first one can be the most impactful, so it's about getting everybody ready."